The broad goal of this work is to examine relationships between sleep and infectious disease. Subjective feelings of sleepiness often accompany infectious disease, and our preliminary results show that sleep patterns are altered in animals with bacterial and fungal infections. The basic hypotheses that sleep patterns are altered in animals with infectious disease and that sleep may promote resistance to disease or aid in the recuperative process will be investigated in this proposal. These issues are of considerable practical importance since: a) sleep may be an important sign of infectious disease, like fever and acute phase responses; b) altered vigilance during disease could seriously and adversely affect a large number of activities (eg., automobile operation); and c) although many individuals undergo periodic sleep deprivation (eg., students, shift workers), the impact of this deprivation upon health and immunity is uncertain. We will evaluate these hypotheses by examining: 1) the effects of bacterial and fungal infections on rabbit sleep, as well as the effects of appropriate therapeutic intervention and the influence of prior immune enhancement or impairment, and 2) the effects of sleep deprivation on immune function and susceptibility to infectious disease. Sleep will be evaluated by monitoring EEG, EEG slow-wave amplitude, and brain temperature. Assays evaluating immune function will include differential white cell counts, plasma cortisol levels, macrophage superoxide production, mitogenic responses of lymphocytes, and splenic antibody production. The proposed experiments will provide insights into both the influence of infectious disease on sleep and the influence of sleep on immune competence, susceptibility to infectious disease, and recuperative processes. Further, they may experimentally identify an adaptive function for sleep.